1. Technical Field
This invention relates to an optoelectronic system, and more particularly to an optoelectronic device that provides non-contact, real time surface digitization of an object using spatiochromatic triangulation.
2. Discussion of Related Art
An increased development of digitization of mock-ups and models for further treatment on CAD systems has led to a need for more effective surface sensing capability in optoelectronic systems. Other measuring and gauging applications, such as scanning machine parts, also requires improved surface digitization. Optoelectronic devices using monochromatic triangulation techniques are a generally well known means for generating a non-contact surface digitization. These techniques often employ coherent light sources that are able to obtain resolutions up to 1 part in 104 depth of field on most types of material. However, systems using coherent sources are susceptible to interference which may create optical noise in the digitization process. In addition, monochromatic triangulation techniques are sensitive to variations in light intensity due to interference effects and surface conditions.
Therefore, it is desirable to provide a high resolution and cost effective optoelectronic system for use with conventional light sources. An optoelectronic system using spatiochromatic triangulation provides non-contact, real time surface digitization of an object. Furthermore, it is desirable to provide a system with a non-coherent light source that results in a measurement technique that is primarily independent of light intensity. Two basic triangulation configurations of the optoelectronic system may be implemented. An xe2x80x9cin planexe2x80x9d and a xe2x80x9cv-shapexe2x80x9d configuration, where the latter configuration decreases the triangulation angle between the light source and viewing plane of the spectrograph and thus avoids occlusion problems associated with conventional triangulation measurement techniques.
Additionally, a surface microstructure compensation technique incorporated into the present optoelectronic system corrects measurement errors caused by surface imperfections.
In accordance with the teachings of the present invention, an optoelectronic system is provided for surface digitization of an object using spatiochromatic triangulation. The optoelectronic system includes an illuminating subsystem for illuminating a measuring space that contains an object to be measured, as well as a viewing subsystem for collecting the light reflected by this object and for generating a three-dimensional topography of the object using in depth chromatic coding of the object. More specifically, relay optics are used to image a polychromatic light source onto a source slit which in turn passes the slit image onto a dispersing element. The object to be measure is illuminated with a continuum of monochromatic images along a cutting plane (x,z) within the measuring space. A color coded (x, xcex) representation, generated by the intersection of the cutting plane and the surface of the measured object, is imaged onto a viewing slit of an imaging spectrograph. A relay lens is used for projecting this image onto the viewing slit. A grayscale imaging array located in the image plane of the spectrograph registers the color coded representation, and by using spectrophotometric analysis, an image processor translates this representation into a plane section of the three-dimensional topography of the measured object.